Heavy rains slam door on Corn Belt planting

Mother Nature did her best to disrupt many outdoor festivities over Memorial Day weekend, and now many Corn Belt farmers with spring planting left to do are facing another round of setbacks.

Rainfall amounts between less than 1 inch to nearly 11 inches fell in the western and central Corn Belt over the last two days, likely throwing the brakes on any planting or fieldwork for at least the next week.

"Abundant rains across west-central portions of the Midwest this past weekend stalled soybean and late corn planting a bit, and additional planting delays are expected across the west-central and north-central Midwest this week," says MDA Weather Services senior ag meteorologist Don Keeney. "Also, the heavy rains will continue to build wetness and flooding concerns, especially across northern Missouri, Iowa, and northern Illinois."

The heavy rains came from a series of mesoscale convective clusters (MCCs) that moved through the area late Monday and early into Tuesday morning. These often massive systems typically build overnight, can comprise a large number of specific storm cells, and are capable of dropping major rainfall amounts like those that fell in the latter half of the holiday weekend.

"The main issue had to do with the three large MCCs that hit large portions of the western Corn Belt -- and specifically Iowa -- over the past three days," says Agriculture.com Marketing Talk contributor and weather specialist WXRISK. "An MCC is a large group of powerful and slow-moving thunderstorms that usually develop during the overnight hours and last through dawn dropping significant rains."

This likelihood of most precipitation coming during overnight hours is nothing new to states like Iowa. In fact, most moisture comes during those hours, just not in the excessive amounts of the last few days. The recent patter goes further to show the immense difference in overall moisture conditions between last year's drought in spring and summer and this year so far.

"During the drought of 2012, this contribution was largely missing. So far, 2013 has been a different story with multiple heavy rainfall events happening during the overnight hours," according to Monday's report from the Iowa Environmental Mesonet. "The featured chart presents the hourly precipitation totals for Des Moines and the long-term climatology for May. The 3 a.m. to 8 a.m. totals have far exceeded climatology. The totals shown were up until 12 a.m. this morning and another .5 inch was fallen today."

Chart courtesy Iowa Environmental Mesonet.

The rain is not just delaying additional plantings, but also likely stripping away acres from this year's total, at least for corn. And it's also causing agronomic issues -- like shallow, weak root structures, which may be tough to overcome enough to reach full yield potential, farmers say.